The Stealthy STD You’ve Probably Never Heard Of

Herpes. Gonorrhea. Chlamydia. Mycoplasma Genitalium. Say what? If you’ve never heard of that last one, you’re not alone. But despite its low profile, there’s good reason to start paying attention to this sexually transmitted infection (STI), known as MG for short. According to experts, it soon could emerge as the next “superbug” — resistant to commonly used antibiotics and extremely difficult to treat.

“Doxycycline is an antibiotic that’s often used to treat STIs, but it’s ineffective against MG,” says Kristin Englund, M.D., an infectious disease specialist at the Cleveland Clinic. The infection is also rapidly developing resistance to a second antibiotic, azithromycin. A third medication, moxifloxacin, can still be used to treat the infection, but the drug is susceptible to resistance and it may not be effective for long.

“Our oral options for treatment are becoming more and more limited,” says Englund. MG was labeled an “emerging issue” by the Centers for Disease Control and Prevention in 2015. And earlier this summer, the British Association of Sexual Health and HIV released new treatment guidelines to help prevent MG from emerging as a superbug, which it said would “undoubtedly lead to a public health emergency.”

Right now antibiotic-resistant MG is a bigger problem in the U.K. than in the U.S., but Englund says it’s only a matter of time before it hops across the pond. “We live in an international world in which resistant organisms are able to move across continents and oceans as people come and go on planes,” she says. “It will be here eventually, and we need to be prepared.”

Although MG was first discovered in the 1980s, one of the problems is that awareness remains pretty minimal, and it’s often mistaken for other STIs like chlamydia. In most cases, MG also doesn’t cause symptoms — especially in women, meaning there’s a chance that you or your partner could have had it for years without even realizing it. According to Englund, between two and four percent of the U.S. population likely has MG, making it more common than gonorrhea (but less common than chlamydia).

In men, the bacteria can cause a urethral infection called nongonococcal urethritis, which is marked by painful urination and discharge. In women, it’s linked to cervical infections and pelvic inflammatory disease — an infection of the reproductive organs that can lead to infertility — although it’s not clear whether MG alone causes either of these conditions. A few studies have even found an association between MG infection and preterm labor.

If you think you could have MG (or any STI), see your doctor right away to discuss testing, since getting the right diagnosis is often the biggest hurdle. Unfortunately, the bacteria can’t be grown in a lab, meaning a quick culture swab won’t deliver an answer. Instead, the only available screening is something called a nucleic-acid amplification test (or NAAT), which can detect the presence of small amounts of bacterial DNA. But this isn’t a standard STI screening, and even if the test is available most doctors will rule out other infections first.

If you’re prescribed antibiotics, it’s important to take the entire dose exactly as directed — don’t chuck the pills if you start to feel better after a few days. “The more the bacteria is exposed to antibiotics, especially an amount that’s too small to wipe it out, the more likely it is to become resistant,” says Englund.

And it goes without saying, once you or your partner has been treated — stay vigilant. In the U.S., rates of sexually transmitted diseases (STDs) are at an all-time high, meaning it’s more important than ever to know your status — and use protection when necessary.